Page 62 - ITU-T Focus Group IMT-2020 Deliverables

2 ITU-T Focus Group IMT-2020 Deliverables

The following figure summarizes the IMT-2020 Network logical and physical abstractions in the form of a
high-level schematic for 5G Network segments and applicable plane specific functionality.

Figure 4 – 5G Logical and Physical Network Segments Viewpoint

I.3.2 Taxonomy of IMT 2020 Network Functionality
The followings represent a taxonomy of IMT 2020 network functionality in separate planes (application /
service plane, Management planes, control plane, forwarding plane) with additional embedded native
softwarization functionality. Although separately specified, the planes functionality is not completely
independent; key items in each are identified as related to items in the other planes. Each plane substantially
uses foundational concepts. However, the planes are sufficiently independent to simplify reasoning about
the complete system specification.
Application and Business Service Plane Functionality – It defines and implements the business processes of
the services along specific value chains. A service in the 5G context is a piece of software that performs one
or more functions, provides one or more APIs to applications or other services of the same or different planes
to make usage of those functions, and returns one or more results. Services can be combined with other
services, or called in a serialized manner to create a new service. An application in the 5G context is a piece
of software that utilizes the underlying services to perform a function. Application operation can be
parameterized, for example, by passing certain arguments at call time, but it is meant to be a standalone
piece of software; an App does not offer any interfaces to other applications or services.
Multi-Service Orchestration and Management (Sub) Plane Functionality – The functions and interfaces in
this plane are used to set up and manage groups of network instances and/or nodes. More specifically, the
setup consists of creating/installing/arranging/deactivation/coordinating NFs and interfaces according to the
available physical and virtual resources. It also comprises the set of functions associated with the network
operations, such as fault management, performance management and configuration management. It further
includes Slice – Service Mapper functions, Resources, Domain and Service Orchestration functions, Service
Information Management functions and Network Capability Discovery functions. It also includes the lifecycle
management of individual network functions and mobile network instances as a whole. In current mobile
networks, this role is often performed by the Operations Support System (OSS). The idea is to enable the

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